How is Tor secure?@ lynks - Thanks. Yeah, that makes sense. And each courier generates its own unique/ pseudo random key based on it's system state at some time. (also @ AJ Henderson) But don't I have to know the key in order to create a lock for it? Then if someone else had this information couldn't they make a key for themselves?

How is Tor secure?Thanks, scuzzy. So the decryption keys are generated at each node independently? Can't someone still reverse the method used to generate the keys and get them that way? Or would they have to know something specific to each node in order to do that?